Reusable water bottles can be plastic, metal, or glass, all environmentally friendly alternatives to disposable plastic. We previously tested plastic and metal water bottles but excluded glass because of weight and durability concerns. However, interest in alternatives to plastic is growing, and glass models have proliferated in the market. We decided it was time to examine them.
We chose six popular models priced from $8.13 to $38.00, ranging in capacity from 16 to 22 ounces, and put them through a battery of tests that included sipping, opening and closing lids, staining, shaking, washing, and, of course, dropping. (Yes, this resulted in a lot of broken glass, even though most models came with a protective sleeve made of silicone or, in one case, nylon. One model was sleeveless, as its glass interior was fully encased in a plastic exterior instead.) We also assigned each model an owner for one week, sending the bottles into the real world—to the grocery store and gym; to restaurants; to yoga, boot camp, and barre classes. The bottles rode in cars, trains, and buses and sometimes just sat around the office, too.
All models passed our staining, odor-retention, and leak tests. Bright red sports drink didn’t color the glass or the undersides of the lids, and while most of the lids smelled faintly fruity if we really sniffed, it wasn’t noticeable while drinking. None of the bottles leaked, even when we turned them upside down and shook them vigorously. They all looked great after 10 washes, too, with no signs of wear and tear. The real differences came down to how easy they were to use. From an aesthetically pleasing model that was a pain to fill to a loud lid that interrupted an otherwise peaceful yoga class, there were clear factors that separated the top performers from the rest.
Every bottle had a screw-on lid. Two were problematic. One had a metal cap, which, like nails on a chalkboard, felt and sounded grating when screwed onto the glass bottle. The other troublesome lid was plastic, with a rigid looped handle that was positioned at a roughly 45-degree angle. The asymmetrical loop made the cap unbalanced and difficult to grip, and the top-heavy lid sometimes fell off as soon as it was unscrewed—both because it was hard to grasp and because the uneven weight distribution caused it to shift to one side. The lopsided handle also made the lid wobbly and challenging to screw back on.
Our top two performers had lids that were far more user-friendly. One model, besides having a screw-on lid, offered an additional option: a button-activated, hinged cap over the drinking spout. It was a cinch to operate, as it popped open with the press of a button. We didn’t have to fiddle with screwing anything off to sip, and though we didn’t always like the loud “pop” that it made upon release—one user said it threatened to disrupt her yoga class—if we held a finger on the lid as we released it, it was quieter.
We liked another model’s plastic screw-on cap with a fixed handle that arched from one side to the other, perfectly symmetrically. While it sometimes took an extra second or two to find the bottle’s grooves, it was relatively easy to close.
Glass water bottles are typically daily-use items, so they need to be easy to wash. Three models were downgraded because they were challenging to clean, for varying reasons.
One, which was hand-wash only, had an excessive seven parts. “It’s not something I want to clean at all,” said one tester. Not only was this model cumbersome to disassemble and wash but we also had difficulty putting all seven pieces back together. Another model had a nylon sleeve, similar to a koozie, that got dirty during everyday use. It soaked up sweat at the gym, giving us an additional item to wash and dry. The third model was downgraded because it had a chain metal loop that was difficult to detach prior to washing and held water if we opted to leave it on; additionally, the silicone sleeve on this model wasn’t very tight and water sometimes got trapped underneath.
Our top models had only two parts to deal with during cleaning: bottle and lid. We also preferred water bottles that were dishwasher-safe, which eliminated the need for a special bottle brush.
Testers had no clear preference in terms of capacity, as it depended largely upon activity and personal preference. At work or home, where bottles were mostly stationary, larger water bottles were advantageous because it meant fewer refills were necessary. At the gym, though, testers said the 20- to 22-ounce bottles (which were roughly 2½ pounds when full) felt heavy to lug around. Some people preferred smaller bottles because they fit well in bags and purses, but one gym-goer with a 16-ounce bottle noted that it was too small to bring to spin class because she didn’t want to have to leave class to refill it. So capacity preferences were situation-dependent, but some models in our lineup, including our winner, come in additional sizes.
We didn’t dock points if bottles broke when we purposely dropped them, as that’s to be expected of glass. Also, larger-capacity water bottles were at a disadvantage because they were heavier. But we did want to gauge the likelihood of damage if a bottle was dropped, so we knocked filled water bottles off a counter onto the floor from three different angles (upright, sideways, and upside down); if they survived, we then dropped them onto concrete, again from three different angles.
Two of the three heaviest bottles—roughly 2½ pounds when filled with water—broke on our hard indoor flooring. The two lightest bottles, by comparison—about 1¾ to 2 pounds when full—didn’t shatter, even when dropped onto concrete. And our winner was an outlier: Despite weighing a hefty 2½ pounds when filled to capacity, it was the only heavyweight bottle to survive all three indoor drops. (Though it did eventually meet its demise outside, on concrete.)
To find out why our winner may have fared better than other similar-weight bottles, we contacted Michael Tarkanian, senior lecturer in the Materials Science and Engineering department at the Massachusetts Institute of Technology. He explained that a glass bottle’s likelihood of breaking can vary a lot depending on how the glass itself was processed, including how quickly it was formed and cooled. Glass thickness is another factor, as is bottle geometry; a sharper bottom edge would be more likely to crack than a rounded bottom. Finally, a protective sleeve that’s thicker and more rubbery would dissipate more energy than a thinner or harder sleeve.
While we don’t know the manufacturing details for each bottle, we did closely examine them all and noticed two traits that may have helped our winner survive when other models broke: It had a more rounded bottom edge, and its walls (which we measured with calipers) were slightly thicker than the others.
Our winner, the Lifefactory 22 Oz Glass Bottle with Classic Cap-Orange ($22.99), had the widest mouth in the lineup, which made it easy to fill, and a lid that we could remove and replace with minimal effort. This bottle was also easy to clean, and as a bonus, it was more resilient than similar-weight models when knocked off a counter. We appreciated the generous capacity, but for those who want a lighter bottle and don’t mind refilling more often, our winner is also available in a 16-ounce size.